Concentric adaptor



FIG. 1 is a perspective view of a concentric adaptor showing our new design;

FIG. 2 is a side view of the concentric adaptor;

FIG. 3 is another side view, in an angle of about 90 degrees rotated from FIG. 2, of the concentric adaptor;

FIG. 4 is an end view of the concentric adaptor;

FIG. 5 is another end view, in an angle opposite to that of FIG. 4, of the concentric adaptor;

FIG. 6 is a cutaway view, cutting through line 6-6 in FIG. 3, of the concentric adaptor.

The graphics and portion of a concentric adaptor shown in broken lines form no part of the claimed design. 

The ornamental design for a concentric adaptor, as shown and described. 